Screening method and application of high efficiency endoxylanase producing strain

Abstract

The invention provides a screening method and application of a high efficiency endoxylanase producing strain. The screening method comprises the following steps: firstly, sample source; secondly, strain screening; thirdly, preparation of xylanase fermentation liquid and the like. According to the screening method, isolated culture of strains is firstly carried out on a growth medium; then the screening of strains is carried out by utilizing a two layer plating method and Azo-xylan (Birchwood) is added into an upper medium as a screening substrate. The method can solve the problem of mixing ofbacterial colonies in the process of firstly culturing microorganisms and then adding a congo red solution for color reaction; in addition, the false positive problem in the process of adding congo red when a plate is prepared and then culturing the microorganisms also can be solved.

Description

technical field [0001] The invention belongs to the field of biotechnology, and in particular relates to a screening method and application of effective endo-xylanase-producing bacteria. Background technique [0002] Hemicellulose is a very abundant resource in nature, accounting for about 35% of the dry weight of plants. It is widely found in agricultural and sideline products such as corncobs, wheat bran, rice bran, straw and bagasse, and its content in nature is second only to fiber white. Xylan is an important part of hemicellulose. It is composed of β-D-xylopyranose units connected by β-1,4-glycosidic bonds to form a main chain with acetyl groups and arabinose residues on the main chain. A variety of different substituents such as glucose residues, main side chains with different sources or branching degrees and different substituents constitute complex and diverse xylan molecules. The complete degradation of xylan requires the participation of multiple enzymes, inclu...

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Problems solved by technology

[0003] At present, the screening of xylan-degrading strains mostly uses the Congo red staining method, mainly through two methods, one way is to culture microorganisms first, then add Congo red solution for color reaction, and then decolorize by sodium chloride to form xylans of different sizes. Sugar degradation transparent circle, the advantage of this method is that the displayed color reaction is basically the effect of xylan degrading bacteria, the disadvantage is that this method is cumbersome to operate, adding Congo red solution will cause mixing between colonies; another method It is to add Congo red when preparing the plate. The advantage of this method is that it is easy to operate and there is no problem of colony mixing. The disadvantage is that agar and potato juice contain starch substances, which can cause false positive reactions in microorganisms that produce amylase. In addition, some Some microorganisms with the ability to degrade pigments will degrade Congo red and form a transparent circle during the long-term culture process, which is not easy to distinguish from xylan-degrading bacteria

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